The California Reaper is a cross between the Carolina Reaper and Jay's Peach Ghost Scorpion made by Steve Bender. Peach is the original color. I found the yellow variant last year in my California Reapers and grew it out to verify it was stable.
The flavor and heat are almost identical to the peach variety. I would say the yellow has a milder flavor and more fruity notes.
These seeds were harvested from plants grown in a controlled environment and isolation to preserve genetics.